1. Field of the Invention
The present invention relates to a color mixing checking method for an inkjet print head and a printing apparatus, and more particularly to a technology for printing a check pattern and for determining a color mixing in ink ejected from the print head with another color ink, based on the printed check pattern.
2. Description of the Related Art
As a checking method for determining whether or not color mixing occurs in ink ejected from a print head used in a printing apparatus such as an inkjet printer and the like with another ink, a method described in Japanese Patent Laid-Open No. H10-151753 (1998) is known. Color mixing of ink may occur in a supply path for supplying ink from an ink tank to the print head. Specifically, a defect that leakage of ink from or infiltration of ink into a supply path for the respective type of ink potentially occur may be detected in a manufacturing process of the print head. In this case, color mixing might occur by that another type of ink infiltrates into the supply path of one type of ink to mix with the one type of ink, and therefore such products need to be subjected to a check in advance. Moreover, in a process in which the print head is used, ink of another color infiltrates into an ejection port of ink of one color due to wiping with rubbing on a head surface, and color mixing of ink may occur, for example. In this case, it is desirable that such a state is detected in advance and the color mixing ink is removed.
In the method described in Japanese Patent Laid-Open No. H10-151753 (1998), by performing sample printing by using ink in a basic color and by optically measuring the color of the sample, it is determined that color mixing has occurred in a case that the measured color is different from an original color.
However, a hue of the printed sample pattern may be different also due to landing position deviation of an ink droplet such as overlapping of the ink droplets ejected to a print medium with each other or separating of the ink droplets from each other or the like. The method disclosed in Japanese Patent Laid-Open No. H10-151753 (1998) cannot discriminate a difference in the hue caused by the landing position deviation from the difference in the hue caused by the color mixing ink. Thus, with the Japanese Patent Laid-Open No. H10-151753 (1998), the difference in the hue not caused by the color mixing ink may be erroneously determined to be caused by the color mixing ink.